The present invention relates to semiconductor devices and, more specifically relates to a semiconductor device in which an integrated temperature sensing and control die is mounted in the same housing as a MOS gated power semiconductor device.
The determination of the temperature of a MOS gate controlled semiconductor device, under transient as well as under steady state conditions, is highly desirable to attain high levels of operational reliability of the device. As an example, the device may be shut down at a predetermined die temperature. Also, overcurrent protection can be attained as a function of the die temperature and time.
Though control and protection circuits may be integrated into the same monolithic chip as the power device to enable direct temperature measurement of the power device, such monolithic devices are complex and complicate the manufacturing process of the discrete simpler power devices. Furthermore, there is less flexibility in the choice of control functions that can be integrated with the power device.
It is therefore desirable to co-package a discrete power semiconductor device with a separate die that includes the control and protection functions. By separating the control and protection functions from the power device, however, the temperature sensing circuitry is mounted at a distance away from the power device or is mounted with the power device on a common substrate that has a relatively high thermal resistance. This separation or thermal resistance prevents the temperature sensing circuitry from readily determining the temperature of the power device junctions. Moreover, the separation and thermal resistance hinder the determination of temperature under transient conditions.
It is therefore desirable that temperature sensing elements in the control die have the capability of accurately and dynamically determining the temperature of the power device.